Werner complexes of metal formates



United States Patent 2,903,456 C Patented; Sept. s, 1959 WERNERCOMPLEXES 0F METAL FORMATES William D. Schaeifer, Pomona, Calif.,assignor to Union Oil Company of California, Los Angeles, Calif., acorporation of California No Drawing. Application November 19, 1956Serial No. 622,836

1 Claims. Cl: 260-270) OOOH wherein M is a metal of atomic number 25 to28 (Le. manganese, iron, cobalt or nickel), and R is methyl or eth 1.

When any of the above complexes are trit-urated with, or precipitated inthe presence of, a liquid mixture of isomeric xylenes, it is found thatthe o-xylene is selectively integrated into the crystal structure,forming what is presently regarded as a clathrate. The solid clathratemay then be separated from the liquid phase, and decomposed with acid orheat to recover the selectively clathrated hydrocarbon.

The new complexes may be easily prepared by simply admixing the propermole-ratios of metal formate and the pyridine base, normally at roomtemperatures, although higher or lower temperatures may be employed. Ifdesired the metal formate may be first dissolved in a solvent such aswater, and the complex precipitated by addition of the pyridine base.The complexes are somewhat soluble in water, but chilling will causeprecipitation of the bulk of the complex, if saturated solutions of theformates are initially employed.

When working in aqueous solutions, it is not essential to start withpure metal formates. Any soluble salt which forms a more soluble complexwith the pyridine base than does the formate may be initially dissolvedin the solvent; formate ions are then added, and finally the pyridinebase, whereupon the less soluble formate complex is selectivelyprecipitated in accordance with the laws of mass action. The complexesof the metal halides are much more soluble in water than thecorresponding formates, and hence it is convenient to use solutions ofmetal chlorides or bromides as starting materials, first adding formicacid, or a soluble formate, then adding the de- 2 sired pyridine base.The resulting'precipitate is then recovered by filtration, washedwith'ether 'or other appropriate solvent, and dried at low temperatures,e.g. 25 100 C. Higher temperatures are likely to causedecomposition.

EXAMPLE I About 26.8 gms. (0.125 mole) of nickel chloride (NiCl -6H O)was dissolved in'30 ml. of warm water, and 11.5 gms. (0.25 'mole) offormic acid added thereto. To the resulting solution was then added 53.5gms. (0.5 mole) of 4-ethyl pyridine. An immediate green precipitate wasformed and considerable heat evolved. The slurry was cooled andfiltered, and the precipitate washed with dioxane and ether, andfinally-air dried at room temperature. The yield was 28% of theoretical,and the melting point was 161 C. with some decomposition. By elementalanalysis the product was found to contain: C62%, H7.0%, N9.7%, Ni-8.l%,and was hence nickel tetra(4-et-hyl pyridine) diformate.

By substituting mole-equivalent proportions of manganese, iron or cobaltchlorides for nickel chloride in the above example, or 4-methyl pyridinefor 4-ethyl pyridine, the corresponding Werner complexes are obtained insimilar yields and purities. The resulting complexes are:

Complex Physical Appearance 1. Manganous tetra i-ethyl pyridine)dliormate White Solid. 2. Ferrous tetra (4-et yl pyridine) diiormate TanSolid. 3. Cobalt tetra i-ethyl pyridine) diiormate.-- Pink Solid. 4.Nickel tetra 4-methyl pyridine) diiormnte. Blue Solid.

5. Manganous tetra (i-methyl pyridine) difor White Solid. 6. Ferroustetra (l-methyl pyridine) diformate" Tan Solid. 7. Cobalt tetra i-methylpyridine) diiormate Pink Solid.

lowing example:

EXAMPLE II About 8 gms. of the complex prepared in Example I wasdissolved with heating in a solvent consisting of 20 m1. of methylcellosolve and 1 ml. of 4-ethyl pyridine. Ten m1. of mixed xylenes werethen added and the solution was cooled whereupon a light greenprecipitate was formed, which was recovered by filtration and washedwith 20 ml. of isooctane. The precipitate was then dissolved in 20 ml.of dilute (50/ 50) HCl, and the solution was shaken with 40 ml. ofisooctane to extract the liberated xylene. The hydrocarbon phase wasseparated and washed with HCl and water and dried over Na SOUltra-violet spectranalysis of the hydrocarbon phase, and of theoriginal xylene, showed that the isomer distribution was as follows:

Table 1 Volume, Percent p-xylene iii-xylene o-xylene Et.Bz.

fiif raaasarrasreianaat 3:3 33:? 231? iii? application SerialNof4663938; filed November 4, 1954, coordinated with substantially fourmoles of 4-ethy1- now-U=S-. Patent'Nm 2,824,463; pyridine.

Other specific complexes methods of preparation and 3. Nickeltetra(4-ethyl pyridine) diformate. uses will readily occurto thoseskilled in the art. The 4. Cobalt tetra(4-ethyl pyridine) diformate.

t'r'uescope of the invention is intended= to'be embraced 5 5. Manganesetetra(4-ethyl pyridine) diformate.

by-thefollowing elaims. 6. Ferrous tetra(4-ethy1 pyridine) diformate.

I claim-rr 7. Nickel tetra(4-met'hylpyridine) diformate. I. AWernercomplexhaving-the formula:

References Cited in the file of this patent i FOREIGN PATENTS 492,660Great Britain Sept, 29,1938 (1160 OJgM;

OTHER REFERENCES- \N Ploquin: Compte rend; vol. 233, pp. 162-164 (1951).

wherein M issmetals Qeammie number 25;- to. 28- inclusive; Hanoberry: J.EcQn;,Entom01ogy,ivol. 35, pp. 915-918 andi R is selected;firmmthci'group consisting ofi, methyll (1942), andethyL, Smith:J.A.C.S., W01. 75, pp. 2010-2012 (1953).

2. Awemer complex: composed. of: oneimoleofi a for Logan: J..A.C.S.,.v0.1- 74, pp. 4194-4195. and, 5224-5 mate; of a5, metat Qf'atomic.xzmrnher 25.- to 28 inclusive, (1952).

1. A WERNER COMPLEX HAVING THE FORMULA: